Intraocular lens and methods and/or components associated therewith

ABSTRACT

An intraocular lens (IOL) has a clear optic and means for actuating change in curvature in at least a portion the clear optic. The intraocular lens (IOL) can have anterior and posterior portions spaced apart by a cavity, and an actuator for urging change in curvature in at least one of said portions, with energy provided by an energy harvesting mechanism incorporated into haptics of said IOL.

TECHNICAL FIELD

Embodiments of the invention relate to intraocular lens and/orcomponents such as haptics or the like that are associated and/or incoupling relationship with such lens.

BACKGROUND

Accommodation

Accommodation is the ability of the human eye to change its opticalpower, in order to focus on objects at various distances. This abilityis gradually lost with age related changes in the eye, resulting in thepatient using reading spectacles or other correction. This condition ofthe loss of accommodation is known as presbyopia and occurs to varyingdegrees in all humans, starting from around the age of 45 and lostcompletely by the age of around 65-70 years.

The principle of accommodation according to the Helmholtz theory, isthat during distance vision, the ciliary muscle is relaxed and thezonular fibers that cross the circumlental space between the ciliarybody and the lens equator are tensioned. When the neural impulse toaccommodate the lens is given by the brain, the ciliary muscle contractsinwards radially and also moves forward anteriorly. This releases thetension in the zonules. The reduced zonular tension allows the elasticcapsule of the lens to contract, causing a decrease in equatorial lensdiameter and an increase in the curvatures of the anterior and posteriorlens surfaces. Such changes in curvature are responsible for increasingthe optical power of the lens and this enables focusing on near objects.When the ciliary muscle relaxes, the zonular tension on the lens equatorrises back to its resting state. This increased tension on the lensequator causes a flattening of the lens, a decrease in the curvature ofthe anterior and posterior lens surfaces, and a decrease in the dioptricpower of the unaccommodated eye.

According to Helmholtz, presbyopia results from the loss of lenselasticity with age. When the zonules are relaxed, the lens does notchange its shape to the same degree as the young lens; therefore,presbyopia is an aging process that can be reversed only by changing theelasticity of the lens or its capsule. This theory is the most widelyheld theory today on accommodation.

Intraocular Lenses

Intraocular lenses (IOLs) are usually implanted in patients withcataracts. A cataract is a condition in which the natural crystallinelens has lost transparency, leading to various degrees of visionimpairment. In the vast majority of cases today, cataract surgeryinvolves removing the cataractous lens, and in its place an IOL made ofa type of acrylic or silicone material is inserted or injected via asmall incision in the outer surface of the eye. IOLs are typicallyplaced in the capsular bag, the original anatomical location of thecrystalline lens, or in the ciliary sulcus which is between the iris andthe capsular bag.

Most IOLs implanted are monofocal and therefore most patients cannotrely on unaided vision for near activities such as reading. There is noaccommodation as the natural crystalline lens has been removed.

The increase in knowledge and widespread effectiveness of cataractsurgery, along with an ever growing and ageing population, has created ademand to increase both the predictability and quality of the visualoutcome, in that the patient will need to rely less on spectacles orother forms of correction. This has also instigated several attempts tosolve the problem of presbyopia.

The first types of IOLs in this regard to be commercialized wererefractive bifocal and diffractive bifocal, trifocal andcontinuous-focus IOLs, which create multiple retinal images ranging fromdistant to near objects. While improving the patient's near andintermediate vision in comparison to monofocal IOLs, these multifocalIOLs cause various photic phenomena such as halos and glare in varyingseverities, and for diffractive IOLs, also diminish the contrastsensitivity at each focus.

The second type of IOLs, known as psuedoaccommodating IOLs, which byusing various mechanical mechanisms, attempt to directly harness andamplify the force generated by the ciliary muscle to create dynamicchanges in focus on demand, thus mimicking the natural youthfulcrystalline lens. These IOLs do not diminish the level of light reachingthe eye from any given object, and do not overlay images on the retinafrom different focal lengths. This IOL type involves use of variouslevers and fulcrums, fluid filled cavities to decrease the rigidity ofthe lens assembly, use of dual optics or magnets. The drawbacks of theselenses are primarily that they either do not create the required amountof optical power change required for reading, or need to be implantedthrough a large incision thus creating iatrogenic corneal astigmatism.

The capsular bag, having been emptied of the crystalline lens, goesthrough a process of regeneration of lens epithelial cells, viamesenchymal cells migrating from the equator of the capsular bag, andfibrosis and contraction of the capsule itself. This changes themechanical properties of the capsular bag and limits its viability totransmit mechanical forces to a psuedoaccommodating IOL. Ciliary musclecontraction during full accommodative effort reaches approximately 0.1mm per diopter in terms of ciliary muscle ring diameter (Richdale et al;Invest Ophthalmol Vis Sci. 2013; 54:1095-1105). This value may be lowerafter cataract or refractive lens exchange surgery due to residualrigidity in the capsular structure that remains in place. However, ithas been found that ciliary muscle movement increases after cataractsurgery.

More recently, another type of lens has been described which useselectrical power to activate a lens made of liquid crystal substances,which then changes the refractive index of the lens, and thus inducingchanges in the optical power. These IOLs do not effectively require anymovement at all, but are currently not flexible and require deliverythrough large incisions.

Electroactive Polymers in Biomedical Implants

Polymers are used in various medical devices due to theirbiocompatibility, application-specific mechanical properties andrelatively easier and cheaper manufacturing methods. Dielectricelastomers have been used in artificial muscle research, and providevery large elongations per unit of electrostatic force due to theirsoftness and high Poisson ratio. Piezoelectric polymers have been usedin active elements in biomedical devices, such as ultrasonic transducersand sensors.

Most of these devices are on the scale of millimeters, and incorporateadditional components such as power sources which further increase theimplant size. This being a relatively unexplored area, a seemingly greatpotential benefit lies in creating structures that utilize electroactiveproperties to maximize the mechanical displacement per the spaceavailable for the device. The goal would be to more efficiently createspatial displacements in structures and devices formed of dielectricelastomers or piezoelectric polymers, by way of inducing voltage at theexternal boundaries of such structures.

However, in order to create large relative strains which would be usefulin a medical implant, large voltages are required. A solution could bein decreasing the thickness of an electroactive element, perhaps tomicro- and nanoscale dimensions, as the electrical field across such anelement is inversely proportional to the element thickness. In this waythe strains may remain small but the cumulative displacement is large.Herein lies a possible obstacle as extremely small structures may not bepractical to manufacture or create enough such absolute displacement.Still, there seem to be a number of unexploited tools on hand toovercome challenges in this field.

US2011/0142806 A1 describes use of electrospun piezoelectricpolyvinylidene fluoride (PVDF) as a scaffold for stem cell culture andtissue engineering applications. However, the PVDF is not part of thefinal engineered tissue.

U.S. Pat. No. 5,522,879 A describes a structure of electrospun PVDF on acollector and can be used as a neural or vascular prosthesis.

In WO 2014100259 A1, a piezoelectric polymer implant is disclosed thatacts as a patch that undergoes flexure and treats the tissue it isattached to by heating, electrical signals or drug delivery.

U.S. Pat. No. 7,128,707 B2 Deals with electroactive polymers asartificial muscles or muscle patches,

US 2011/0152747 A1 discloses a medical device made of an electroactivepolymer covered by a photovoltaic layer.

Piezoelectric polymers have also been described as energy harvestingdevices. In US 2011/0275947 A1 PVDF is used as a power source for acardiac implant, utilizing the natural motion of the heart's contractionand expansion to create an internal voltage.

WO 2015123616 A1 Discloses a vibration sensor for detecting motion inthe ciliary muscle. The device is a thin film piezoelectric polymermounted between a pair of electrodes on a silicon base in a cantileverstructure.

US 20140192318 Al is an external device for detecting electric activityin the ciliary muscle.

US20140240658 is a sensor mounted on an ophthalmic lens that detectschemical or photonic stimulus, with a power source, power managementcircuitry, clock generation circuitry, control algorithms and circuitry,and lens driver circuitry.

US 2007/0260307 A1 Describes an IOL that is actuated by a dielectricelastomer.

U.S. Pat. No. 8,834,566 B1 Describes an IOL with a pair of electroderings that by attraction changes the curvature of a fluid mediumsandwiched between two lenses, also creating axial translation. Thismethod however may be limited in displacement as the electrodes do notcover a large area of the optic as they are not transparent or flexible.

One of the more promising methods for energy harvesting is thetriboelectric effect. Two materials in intermittent contact with eachother create contact electrification which passes charge from one to theother. A chemical bond is formed during the contact, and theelectrochemical potential is equalized by the passing of charge betweenthe materials by electrostatic induction. A similar process occursduring separation, although the charge is typically not the same as withcontact. However, contact itself may not be necessary when one materialis an electret, having a quasi-permanent charge and therefore allowing acharge to build up on an opposing conductor (S. Niu, Z. L. Wang,Theoretical systems of triboelectric nanogenerators, Nano Energy 2015).

US 2014/0084748 A1 and US 2014/0246950 A1 are examples of suchtriboelectric nanogenerators.

SUMMARY

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, tools and methods which aremeant to be exemplary and illustrative, not limiting in scope.

In an embodiment, there is provided an intraocular lens (IOL) comprisinga clear optic and means for actuating change in curvature in at least aportion the clear optic.

In another embodiment, possibly combinable with the formerembodiment(s), there is provided also an intraocular lens (IOL)comprising anterior and posterior portions, possibly multiple anteriorand posterior portions, possibly clear optic portions, spaced apart by acavity, possibly multiple cavities formed between any two said portionsand each portion being at least partially formed from transparentmaterial, and an actuator for urging change in curvature in at least oneof said portions.

In a further embodiment, possibly combinable with the formerembodiment(s), there is also provided an intraocular lens (IOL)comprising a clear optic and an actuator for urging change in curvaturein at least a portion of the clear optic, wherein the actuatorcomprising a stack of electroactive material layers (EAMs) withinterdigitated electrodes.

In yet a further embodiment, possibly combinable with the formerembodiment(s), there is provided a haptics for coupling to an optic bodyof an intraocular lens (IOL) of at least any one of the formerembodiments, wherein portions of the haptics comprise an energyharvesting mechanism.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by reference to thefigures and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE FIGURES

Exemplary embodiments are illustrated in referenced figures. It isintended that the embodiments and figures disclosed herein are to beconsidered illustrative, rather than restrictive. The invention,however, both as to organization and method of operation, together withobjects, features, and advantages thereof, may best be understood byreference to the following detailed description when read with theaccompanying figures, in which:

FIG. 1 schematically shows an embodiment of an intraocular lens of theinvention;

FIG. 2 schematically show various embodiments of intraocular lens of theinvention;

FIG. 3 schematically show additional embodiments of intraocular lens ofthe invention;

FIGS. 4 to 6 schematically show various components of intraocular lensesand/or haptic embodiments of the invention;

FIG. 7 schematically shows a flow chart illustrating various possiblecomponents of intraocular lenses and/or haptic embodiments of theinvention; and

FIG. 8 schematically show possible arrangement of intraocular lensesand/or haptic embodiments in relation to elements of a human eye.

FIG. 9 schematically show possible arrangement of intraocular lensesand/or haptic embodiments in relation to element of a human eye.

DETAILED DESCRIPTION

Electroactive Actuating Lens Element

In the first aspect, the present invention addresses the problem ofpresbyopia by an IOL, part of which consists of an optical lens element,made of optically transparent material. This transparent material may bepiezoelectric or a dielectric elastomer.

In the discussion herein, the terms transparent lens element, opticallens element and membrane refer to the same component. Furthermore, inthe various aspects of the invention discussed herein, the termtransparent may refer to being optically transmissive to at least 90% ofincident visible light.

A piezoelectric material deflects when an electric field is applied,depending on the direction of the field and the coupling coefficient ofthe material for the given direction. A dielectric elastomer is apassive, minimally compressible material, that when sandwiched betweentwo compliant electrodes, can convert the electrostatic attraction orrepulsion between the charged electrodes into mechanical energy. This isdone by a change in the thickness of the layer. An in-plane strain isinduced that changes the surface area of the elastomer.

When such an electroactive layer is formed with a directional bias init, such as in a concave-convex or convex-concave lens, with a clampedboundary condition on the edge of the layer, the forces result indeflecting the layer in the direction of the bias.

The membrane of an electroactive material may be cast molded, injectionmolded, drawn or pressed from molded or extruded sheets and cut to size,electrosprayed or spin coated from melted granules or from solution on asubstrate or any other suitable method to achieve thickness, polingdirectionality (in the case of a piezoelectric material) andtransparency, such that is known to those skilled in the art.

The transparent lens element is in contact with one or both of itssurfaces with an electrode.

In one or more embodiments, the electrode is transparent, and is in turncoated or connected to another transparent material of high refractiveindex or different refractive index to the transparent electrode layerand/or to the piezoelectric/dielectric elastomer element. The purpose ofthis layer is to serve as a pre-prepared substrate in the manufacturingprocess, and to increase the optical power at the interface between thesurrounding aqueous humour and the lens assembly.

In another embodiment the transparent electrodes have a refractive indexlarger than the refractive index of the piezoelectric element.

The electrodes may also be opaque, and remain outside the clear opticdiameter.

In another embodiment the electroactive material may cover a certainportion of the lens surface, so that the electroactive element is formedas an annulus. The diameter of the smaller inner circle of the annulusmay be from 1 micrometer up to 6 mm (in which the deflection forces arecreated at the edge of the lens element).

In an aspect of the invention applicable to most embodiments, theelectroactive material (EAM) and electrodes preferably cover asubstantially full portion of the lens surface, and said EAM andelectrodes being substantially transparent. Such full coveragepreferably optimizes displacement of the actuator and consequentlychange in curvature of at least a portion of the clear optic and in turnoptical power of the IOL.

FIG. 1 shows a basic example of an optic body 100. The optic body 100includes a thick ring 110 at its periphery (shown in section, thicknessmay be between about 100-500 micrometers) which is attached to a lens120 of the optic body. The lens (possibly including the ring) may becomprised of a transparent polymer (130, 140) similar to commonintraocular lens materials, such as hydrophobic acrylic, hydrophilicacrylic, silicon or the like. In this example the transparent polymer ison both sides of an actuator, however in some examples the actuator maybe formed or located on one outer side of one or more transparentpolymers. In some examples, the actuator may form the clear optic lens120 without any polymer such as polymer 130, 140 associated therewith.

Polymers layers 130, 140 at least in certain embodiments may serve as apre-prepared substrate in a manufacturing process, inter alia, forpurpose of increasing the optical power at an interface between thesurrounding aqueous humour and the optic body (which may also bereferred to as a lens assembly).

In one embodiment one or more of such polymer layer and/or substratelayer may comprise of a polymer shell or container that is filled with afluid or soft gel that is relatively soft and compliant so that possiblyit does not hinder movement of the actuator. The material of the polymershell may be at least one of a hydrophobic acrylic, a hydrophilicacrylic, silicone or the like. The material of the fluid or soft gelwithin the shell may be an at least one of silicone oil, an elastomersuch as: polydimethylsiloxane (PDMS) which may be optically transparentand soft.

The elastomer type used preferably has a relative high elongation(possibly above 100% as measured in room temperature) and low ShoreHardness (for example measured according to ASTM D2240). Alternativemetrics of the material softness may include having a low Young'smodulus. In one example, a low Shore Hardness may possibly be betweenabout 10 [Shore 000] and about 100 [Shore 00], and preferably belowabout 70 [Shore 000]. In one embodiment, a lower limit for the Shorehardness may be chosen to be about 30 [Shore 000] so as to limit risk ofthe substance within the shell from being dispersed within the eye in anevent where a breach in the shell is adversely formed.

The actuator may include electrodes (possibly at least partiallytransparent) 131 and 132 that are negative and positive, respectively;for example made of PEDOT:PSS. The actuator includes an electroactivematerial layer (EAM) 133 that in one embodiment is a piezoelectricpolymer, also transparent, for example made of PVDF. In anotherembodiment the EAM 133 may be made of a dielectric elastomer such aspolydimethylsiloxane (PDMS) or optically transparent and soft siliconeelastomer. The elastomer type used preferably has high tear strength andelongation and a low Shore Hardness. The arrows 134 are a representationof the poling direction (if a piezoelectric material is used), in thiscase parallel to the direction of the electric field. Dimension T2 isthe overall thickness of the lens 120, for example between 1 and 400micrometers. T1 is the thickness of the EAM layer of 133, for examplebetween 1 and 1000 nm. Possibly, the electrode thicknesses E1 and/or E2may be up to 1 order of magnitude to T1. For example, for a T1 being 0.5micron, E1 and/or E2 may have a thickness between 0.5 micrometers and 5micrometers.

In the context of the present disclosure, a lens including and/or beingassociated with an actuator may be also referred to as an actuatinglens.

The curvature of this lens can be changed by applying voltage betweenthin and transparent electrodes 131, 132 in contact with the EAM. Theelectrode material may be spread over the clear optic of the lens andthen preferably may be transparent, or be in contact with differentareas of the lens and then may not necessarily be transparent, such aswhen using silver nanowires/nanoparticles as electrode material.

The curvature changes are calculated via an eye model, which takes intoaccount biometric parameters of the eye, published in literature andknown to those skilled in the art.

Such an eye model may be the Navarro-Kooijman (Navarro R, Santamaría J,Bescós J. Accommodation-dependent model of the human eye with aspherics.J Opt Soc Am A. 1985; 2:1273-1281, A. C. Kooijman, “Light distributionon the retina of a wide-angle theoretical eye,” J. Opt. Soc. Am. 73,1544-1550 (1983)), Liou-Brennan (Liou H, Brennan N. Anatomicallyaccurate, finite model eye for optical modeling. J Opt Soc Am A. 1997;14(8):1684-1695.), or any other eye model commonly in use in intraocularlens design by those skilled in the art.

Within the eye model a lens is defined to provide an effective focallength of approximately 0 Dioptres (“0D”) in one state, and a higheroptical power in another state, and so doing can provide a range of focibetween the two states, in a dynamic fashion according to the voltageapplied to the actuator. This higher optical power may be 2.5D, 3D,3.5D, 4D or higher.

In FIG. 2, the left optic body 100 shows a cross sectional view of thebody's lens curvature in resting state, or the “0D” state. This may bethe situation before the voltage is applied. That is to say that in atleast some embodiments after cessation of application of voltage, a lenscurvature preferably elastically returns to its resting state, where ina case of dielectric elastomer based lens cessation may includedischarging a voltage present across the EAM and in a case of apiezoelectric lens after cessation voltage decays across the EAMpossibly with no assistance. The right optic body 100 represents thecurvature in an actuated state, e.g. in a “4D” state, in which the lensis focusing the image from near objects onto the retina. Whenprogressing along optical axis A the curvature of this lens may beconvex-concave or concave-convex (as illustrated in the right body 100),and may change between these states during actuation. For example theresting state may be a convex-concave lens, and the actuated state maybe a concave-convex lens or stay convex-concave.

Flipping between convex-concave and concave-convex states (orvisa-versa) may be achieved, for example in an embodiment of an actuator1200 shown in FIG. 2a possibly combinable with actuator 120. Hereactuator 1200 is embodied as comprising dielectric elastomer material.Actuator 1200 has anterior and posterior surfaces 1201, 1202. The figureillustrates a setting of a given polarity on an electrode 213 on atleast a portion of one surface 1202 (posterior for example, negative),and opposing polarity on an electrode 212 on at least a portion of thesecond surface 1201. The bottom enlarged section illustrates a contactpoint 210 (anterior, positive) for providing electrical charge tosurface 212. The periphery of here the anterior surface has in thisexample negative polarity on a separate electrode 211 shaped as anincomplete annulus, with the break around the positive contact point210. Thus the posterior electrode 213 and the annular electrode 211repulse initially, creating a flipping of the actuator's bias in itsperiphery in terms of deflection, shown in FIG. 2b . In a directionalong optical axis A, the left state of actuator 1200 illustrates aconcave-convex shape, just before being flipped. The middle state ofactuator 1200 illustrates a flipped peripheral area 216 and a centralarea 217 which is flattening towards a flipped convex-concave shape asillustrated in the right state of actuator 1200 to result in a possiblyfully deflected convex-concave shape 215. Flipping may be done graduallyaccording to the accommodation demand. This is because the electrostaticrepulsion increases the localized thickness of the elastomer in anannular section defined by electrode 211 thus creating an in-planetensile stress on the central area of the lens, which pulls it taut intoa flatter curvature.

In one aspect of this invention different ranges of maximal near visioncorrection may be suited to different patient needs. This may be done byevaluating the available range of motion occurring during accommodationfor a given patient and tailoring the response of the actuatoraccordingly.

Far Vision Lens and Actuating Lens Arrangements

In another aspect a series of lenses may be defined within the eye modelto describe a range of optical powers for far vision correction. In thiscase there may be a separate and independent lens defined to provide aneffective focal length suitable for far vision correction, and anotherlens which is the dynamically accommodating lens that can change itscurvature between the two states as described herein before.

Far vision correction includes rotationally symmetric and rotationallyasymmetric optics such as in toric optics. The form of this far visioncorrecting lens may be biconvex, convex-concave, concave-convex,biconcave or any other form that may achieve the optical power required.The optical power required may be a small correction following othersurgical procedures conducted on the patient's eye. Additionally thelens surfaces may be aspheric in such a way that controls theaberrations of the optical system, in any manner known to those skilledin the art.

FIG. 3a shows an example of an optic body arrangement of convex andconcave lens surfaces 300, 301 which provide the baseline optical powerfor far vision, in this example on the anterior side which is to theright of an optic body arrangement 3000. Possibly, the baseline opticalpower for far vision may be on the anterior side in order to avoidinterference with the iris and/or pupil. Here the posterior lenssurfaces are concave-convex 302,303. Alternatively as in FIG. 3b theposterior lens is convex-concave 304. Furthermore, the posterior lensmay be connected to the far vision lens by way of a bridge or connectingfeature 306, shown in FIG. 3c that is included or part of ring 110 showne.g. in FIG. 1, which provides the necessary rigidity in holding theactuating lens in place on the optical axis. Between the lenses is acavity 307 to prevent interference in movement of the actuating lens.The dotted profile of an actuating lens in the “0D” state is shown in305 (see FIG. 3C). Bridge 306 may be provided with passages orfenestrations (see 550 in FIG. 5b ) to permit fluid communicationbetween cavity 307 and an exterior medium within the eye.

In one embodiment such a cavity 307 may be filled with a substance suchas silicone oil or soft gel, having a different refractive index to theaqueous humour surrounding the lens, in order to allow for optical powerchanges that occur when radius of curvature is changed in the actuatinglens. In the case of a cavity filled with silicone oil, to avoid leakageof oil into the aqueous humour, the passages in bridge 306 may lead to afluid reservoir 308 allowing communication of the silicone oil from thecavity to the reservoir.

Such configurations are non-limiting and depend on the requirement ofthe patient, for example if the patient already has undergone cataractsurgery and has an IOL in the capsular bag. In this situation aposterior concave surface may be desirable in order to avoid contactwith the primary IOL, though if the deflection is small that may not benecessary. Furthermore the far vision lens may be of a lower dioptre,intended for small corrections as a secondary intervention. The farvision lens may of course also be the posterior lens in the arrangement.In another exemplary configuration, the lens is arranged to have ananterior lens for partial correction of far vision, then moreposteriorly the near vision actuating lens, and then an additional moreposterior lens for the remainder correction of far vision. This examplehas two cavities formed by three lenses. In this way the thinner nearvision lens is protected by the far vision lenses from damage caused byhandling on both of its sides.

Stacking of Actuating Layers

In another aspect an actuator according to certain embodiments of thepresent invention may include a stack of electroactive material layers(EAMs) with interdigitated electrodes that form a multimorph, toincrease the possible deflection of the actuator and enable thickerindividual EAM thicknesses and/or lower operating voltages. This isbecause a single EAM may be difficult to handle in manufacturing, andthere may be a benefit in improved mechanical stability should theoverall thickness of the actuator and/or lens be increased.

FIG. 3d shows a typical example of a plurality of layers comprising amultimorph. Electrode 308 is here a positive electrode, EAM 309 is apolymer element that may be a dielectric elastomer or a piezoelectricpolymer. Electrode 310 is here a negative electrode. Then again EAM 311is a dielectric elastomer or a piezoelectric polymer, electrode 312 apositive electrode, EAM 313 a dielectric elastomer or a piezoelectricpolymer, and electrode 314 a negative electrode. Substrate transparentpolymers 315 and 316 may be the materials typically in use inintraocular lenses, such as acrylic or silicone materials. In the caseof dielectric elastomers the positive and negative electrodes in thefigure attract electrostatically and compress the elastomer, creating anin-plane strain that increases the surface area and therefore creating achange in the curvature of the lens. The multiple layers of themultimorph cause an accumulation of strain that increases the curvaturein an amplified manner for a given electrical field. The benefits may bethe ability to decrease the required operating voltage and the abilityto increase the thickness of the element, making for easier handling andless susceptibility to manufacturing defects.

Actuator Formed with a Dielectric Elastomer and Compliant Electrodes

For a single membrane of dielectric elastomer, sandwiched between twocoated transparent electrodes, an overall thickness of t₁ can bedefined, with t_(el) being the thickness of each of the electrodes andt_(mem) being the membrane thickness of the dielectric elastomer.

The in-plane stress σ_(inpl) that causes the membrane to stretch andthus increase its surface area is defined by the electric field acrossthe membrane E and the relative permittivity of the dielectric materialϵ_(r). This is also known as the Maxwell stress:

${\sigma_{inpl} = {\frac{1}{2}ɛ_{0}{ɛ_{r}\left( \frac{V}{t_{mem}} \right)}^{2}}},$

Where

${E = \frac{V}{t_{mem}}},$

and V is the voltage. ϵ₀ is the permittivity of the vacuum.

For deflection of circular clamped plates, in the case where thedeflection y is above half of the membrane thickness, a solution forstress σ_(flex) is given by Roark's formulas for stress and strain(Seventh edition, Young and Budynas, McGraw-Hill ch.11 pp 448):

$\frac{\sigma_{flex}a^{2}}{{Et}_{1}^{2}} = {\frac{K_{3}y}{t_{1}} + \frac{K_{4}y^{2}}{t_{1}^{2}}}$

Where σ_(flex) is the deflection stress, a is the outer radius of theplate, E is the Young's Modulus, t₁ the overall thickness of the plate,

$K_{3} = \frac{2}{1 - v}$

(at the center or tne plate, v being Poisson's ratio of the materialwhich is taken as 0.5 for a soft dielectric elastomer with compliantelectrodes), K₄=0.5. The assumption that the plate is flat is areasonable approximation, as the initial radii of curvatures are largerby 2-3 orders of magnitude (R>>a).

The deflection required is defined by the difference in the sagittalheights of the initial “0D” state when the actuating layer is at restand the various actuated states which are achieved under differentapplied voltages (“XD”, where the X indicates a certain dioptric valuesuch as “4D”):

$y_{XD} = {\left( {R_{XD} - \sqrt{R_{XD}^{2} - a^{2}}} \right) - \left( {R_{0D} - \sqrt{R_{0D}^{2} - a^{2}}} \right)}$

Where R_(XD) is the radius of curvature of a given state and y_(XD) isthe deflection at the given state. Here the non-limiting assumption of aspherical (rather than aspheric) surface is made.

Solving with given y values, known membrane dimensions t₁, t_(mem), anda, with the known material properties of Young's modulus and relativepermittivity, the voltage can be found that satisfies σ_(inpl)=σ_(flex).

For multiple stacked dielectric elastomer membranes with interdigitatingand compliant electrodes, a number of layers N may be introduced intothe equation such that each layer reduces the required deflection ofeach individual layer, and correspondingly increases the overallthickness such that:

${y_{{XD}_{{individua}l\_}{layer}} = \frac{y_{XD}}{N}},{and}$t_(1_(individual_(layer))) = t₁ × N.

The electric field E is unchanged for a given individual layer as thesame voltage is applied as in the case of the single layer describedabove.

FIG. 3e shows an example of a simulation of a “4D” deflection of anactuating lens, in a paraxial version of the Liou Brennan eye model orsubstantially similar thereto. The actuation voltage that satisfiesσ_(inpl)=σ_(flex) is plotted against the individual layer thicknessesranging from, in this example, 50 nm to 100 nm. Various numbers oflayers N are used to show how increasing N may allow reduction of theactuation voltage and/or the individual layer thickness.

Actuator Formed with Piezoelectric Electrospun Nanofibers

In a further aspect of the invention, the EAM may be one or morepiezoelectric micro- or nano-fibers. In one embodiment these fibers maybe applied to the transparent electrodes on the substrate surface byelectrospinning. The electrospinning may be accomplished by variousmethods such as near field electrospinning, air assisted far- or middle-field electrospinning or electrospinning using an auxiliary electrode toguide the fiber.

The objective in this case would be to create a pattern of thepiezoelectric fiber on the surface in such a way that it can deflect ina manner that accumulates the deflection along the length of the fiber.

The fiber is electrospun in a way that maintains a fiber diameter thatis similar to that of a single piezoelectric membrane layer as describedabove (1 nm to 1000 nm), but has improved poling directionality in thatits poling extends along the fiber length, due to the electrospinningprocess. The poling direction is along the 3 direction which is parallelto the length dimension of the fiber.

This further increases the size of the deflection vector in the desireddirection. For instance as shown in FIG. 4, if the electric fielddirection E is transverse to the fiber 400 as in the 2 direction, ashear strain can be achieved, resulting in deflection as in 401 in the2-3 plane. Deflection may be positive or negative depending on the signof the coupling coefficient (d₂₄ or d₁₅) of the material selected.

FIG. 5 shows a short segment of a pair of fibers 500, 510 deposited byside-by-side electrospinning onto the surface of a substrate 530 such asa transparent acrylic polymer. The piezoelectric material fiber 500 iselectrospun together with an electrode fiber 510 such that aninterfacial surface 540 exists between the fibers in order to createelectrical contact. The electric field created by the charge 504 is inthe “1” direction, and the poling direction is in the “3” direction(503). The strain in this case would be shear around the “2” axis aswith 501. Again here depending on the sign of the coupling coefficientthe direction of the strain about axis “2” is defined. The thicknessdimension of the substrate 520 may be as described above (1 micrometerto 300 micrometers).

The electrode 510 may also be e.g. separately printed, rather thanside-by-side electrospun.

Should the fibers be patterned as a continuous spiral as in oneembodiment, such a strain may create a rotation around the 1 axis andwould possibly create expansion in the radial direction of the elementwhen voltage is applied. FIG. 5c shows an optic body 100, on which aspiral fiber is patterned. Shown in Detail A of FIG. 5c , the centralregion 575 of the optic body may be the starting point of the spiraldeposition, with a first electrode or electrical contact point 573. Thespiral is constructed in this example of a side-by-side electrospunpiezoelectric material 571 and a transparent conductor 570 that isconnected to the first contact point 573. The pitch of the spiral may besuch that there is a gap between each spiral arm so that there isn'telectrical contact between said arms. The poling direction 576 is shown.

The end point of the spiral deposition (shown in Detail B of FIG. 5c )may be again with the transparent electrode 570 being in contact with asecond electrical contact point 572. The region of the substrate outsideto where the spiral is deposited is also shown 574. By creating avoltage difference between electrical contact points 573 and 572, adeflection may be caused via the piezoelectric effect, accumulating overthe length of the spiral.

In another embodiment the fiber is a hollow tube which further increasesthe ability of the fiber to deflect by increasing the couplingcoefficient compared to the solid fiber (Cheng-Tang Pan, Chung-Kun Yen,Shao-Yu Wang, Yan-Cheng Lai, Liwei Lin, J. C. Huang and Shiao-Wei Kuo,“Near-field Electrospinning Enhances the Energy Harvesting of HollowPVDF Piezoelectric Fibers,” RSC Advances Vol. 5, pp. 85073-85081, 2015).

In another embodiment the fiber is coaxially electrospun with atransparent conductor as the core material.

In another embodiment the fiber is coaxially electrospun with atransparent conductor as a core and as and outer layer around thepiezoelectric material.

In another embodiment, each spiral of side-by-sidepiezoelectric-conductor fiber (as shown in FIG. 5c ) is encapsulated orpartially encapsulated (with the electric contact points exposed), andspirals are deposited in a stack, forming a multimorph.

In another embodiment as shown in FIG. 5d , the pattern of a givenelectrospun layer is a set of concentric circles of fibers 582, each ofwhich is electrospun side by side with a fiber of conducting materialserving as an electrode (as shown in FIG. 5c ), such that each fiberpair is deposited starting at one segment of the lens 580 and ending atanother segment 581. Outside of the lens clear optic may be a positive583 and negative 584 electrode, to which the start 580 and ending of thefiber pair 581 are in electrical contact with

Structural Overview of a Device

With attention drawn to FIGS. 6 to 8, aspects relating to variousembodiments of haptics combinable with the various embodied optic bodiesof the invention will be discussed.

Haptics continue from the optic body towards the equatorial contactarea, either with the ciliary sulcus or in the capsular bag.

There may be various openings or fenestrations created in the peripheryof the body (e.g. in ring 110 and/or bridge 306 discussed above and/orin adjacent regions thereto) to allow for the aqueous humour topenetrate into a space (e.g. cavity 307) between two lenses of an opticbody (e.g. body 3000). This may be beneficial for manufacturing reasonsand also to avoid having an additional material in this space whichincreases the overall bulk.

FIG. 5a shows a C-loop design haptic 554, wherein the optic body 555 isfenestrated on its periphery. The optic-haptic junction 553 providessupport between the haptics and the two lenses in this example, as shownin FIG. 5b an anterior lens 551 and a posterior lens 552. Fenestration550 is illustrated in the enlarged section of the view in FIG. 5b (beinga peripheral view)

Piezoelectric Motion Sensor and Haptics

The motion of the ciliary muscle is generally characterized into twosignal types, namely a high amplitude, low frequency set of signals ofbelow 1Hz that correspond to the main contractions and expansions of theciliary muscle (i.e. accommodative responses), and range of lowamplitude, higher frequencies, that correspond to various backgroundmuscle responses. These may be for example reactions of the body tofatigue; caffeine; fluctuations in intraocular pressure; adrenaline orconstriction of the pupil as a reaction to ambient light changes. Smallperturbations in the eye motion or saccades may also be a cause for highfrequency motion of the ciliary muscle.

In an aspect of the invention, a motion sensor may be incorporated inthe haptics. This motion sensor may have a multiple role in that itdetects motion of an accommodative response, of various amplitudesdepending on the accommodative stimulus, and also in detecting smallmotions at higher frequencies that the muscle undergoes constantly.

Shown in FIG. 6, is an embodiment of a motion sensor 600 comprising inthis example a plurality of highly aligned fibers (forming a fiberarray) of piezoelectric polymer, included in a haptic 601 which isconnected to an optic body 602 (sensor is here illustrated beingincluded in one of the haptics, however sensor 600 may be included inmore than one in this example possibly in all haptics of this 4-loophaptic design that is shown).

In FIG. 6 and in the enlarged section in FIG. 6a , sensor 600 isillustrated accordingly including a plurality of highly aligned fibersof piezoelectric polymer, in connection with two electrode vias 611 and612 that communicate with a control unit 613, with various components apossible embodiment of which is shown in the flow chart in FIG. 7. Themotion of ciliary muscle applies force on the haptic loops in contactwith it, and creates in the sensor embodiment 600 a possible buckling,bending and/or shear force on the fibers. This induces a voltage acrossthe fibers, either high enough for overcoming a threshold required toinduce motion in the actuating lens and/or to harvest energy to maintainthe actuated state.

In an embodiment, motion sensor 600 may also take the form of aplurality of fibers deposited on a thin substrate, either on the hapticsas seen e.g. in FIG. 6 or bounded by the haptic and the optic body asseen e.g. in FIG. 6b where that the fibers may possibly be formed in a“serpentine” shape zig zagging continuously back and forth between thehaptic and optic body. The direction of the ciliary muscle movement,especially the circular muscle fibers which are sphincteric, is mainlyin-plane with the haptics and radial, and thus the direction of thesensor fibers is preferably along this radial direction.

The electrospun piezoelectric material may form a single fiber or abundle of fibers, either twined, braided or in parallel.

FIG. 6b shows an example of an exaggeratedly sparse (for illustrativepurposes) serpentine electrospun fiber (or fiber bundle) 622, connectedbetween the haptic and optic body (shown on just one of the sides of thelens), and having two electrical contacts at 620 and 621. The serpentineshape may be deposited by a CNC-type motion along the profile of thehaptic and optic design outline. In an embodiment, the fibers may bedeposited on a thin substrate, and then either removed as a sacrificiallayer once the fibers are deposited thickly enough to support their ownweight or left in place.

The piezoelectric material may be electrospun side-by side or coaxiallywith a conducting material, or as a composite material such asPVDF-TrFe, PVDF/Graphene Oxide, and PVDF/MWCNT. This may increase then-phase content of the material, and reduce the fiber diameter, as isknown to those skilled in the art.

The fiber of the motion sensor may cover any portion of the hapticseither in addition or instead of the forms shown above.

In an embodiment of the present invention, haptics, which are thecontinuation of the optic body which holds the optical elements, aredescribed. These haptics are shaped in a way that mechanically supportsthe optic body and maintains the axial position of the entire lens, aswell as its centered position on the optical axis. At the same time, atleast a portion of the haptics should be flexible in order that theyfold or bend, at first for the delivery through the small incision inthe cornea or limbus, and enough that the energy of the ciliary musclebe transmitted to the motion sensor.

In various embodiments, the entire haptics are shaped in the common ormodified C loop type shape, 4 slotted or unslotted loops, 3 slotted orunslotted loops, slotted or unslotted plate haptic, such that is knownto those skilled in the art.

In some embodiments the haptics are formed (possibly from an acrylic orsilicone material or the like), to be thicker in a base close to theoptic body of the lens in order to prevent unwanted deformation of theoptical structures of the lens, caused by eye movements or ciliarymuscle movements. Alternatively or in addition, the thickness may bemaintained substantially similar as in the base or change according todesign considerations and in addition a geometry may be employed thatmoves a flexure point of the haptic to a certain distance from theoptical structures of the lens. For example, in the embodiment seen inFIG. 6b , a flexure point 625 is illustrated distanced from a base 623to form a resilience region at a vicinity of point 625 about which anarm 627 of the haptic more distal from the optic body may be movable inrelation to a leg 629 more proximal to the optic body.

In an embodiment, a fiber array such as fiber 622 (or equally fiber 600seen in FIG. 6a ) may be formed beyond flexure point 625 in a region ofthe haptic (e.g. arm 627) to sense motion in a region of the haptic moresusceptible to motion.

FIG. 6c shows haptics that are angulated in order to avoid iris chafe, acommon risk for sulcus placement of planar or zero degree angulationIOLs.

In haptic embodiments including a slot (seen e,g, in FIG. 6) the fibersmay accordingly be deposited across the slot, so that ciliary musclemovement creates a buckling in the fibers and a resulting current in theelectrodes at each side of the slot. Alternatively instead of a slotsome haptics may be formed in a zigzag or Z shape (not shown), and thepiezoelectric fibers may be deposited across the gaps between thehaptics in a radial direction. In another embodiment the piezoelectricfibers are deposited along the shape of the haptic (possibly along acontour of the haptic) instead of and/or in addition to just across thegaps. In this way the fibers also react to deflection modes other thanbuckling. In this embodiment each fiber has either a pair of electrodesat each of its ends, with or without a side by side, coaxial orcore-and-shell electrospun electrode.

In another embodiment the sensor is a piezoelectric thin membrane ormultimorph stack of membranes that are coated on the haptics withinterdigitating electrodes, and thus harvesting multiple modes of forcesapplied by various movements of the eye and the ciliary muscle inparticular. The membrane may also be formed across gaps between thehaptics as contiguous single or multilayer membranes or formed as stripsof the same.

In another embodiment the haptics themselves are formed of electrospunfibers (as described above, in an aligned or non-aligned manner),possibly onto a flexible conducting substrate, such that theconcentration of sensors or harvesters is greatly increased. Increasingthe concentration of the harvester units improves the yield of theenergy gain per unit volume. This is done by reducing the spacingbetween fibers to pack them into a smaller surface area per fiber (i.e.to form a 3D haptic structure created from adjacently deposited fiberswith substantially limited spacings therebetween). Fibers may bedeposited in individual line segments or be continuous in a raster orzigzag shape (inter alia on the anterior and posterior surfaces of thehaptic), or in a bending beam transduced configuration (on the plane ofthe haptic normal to the direction of movement of the ciliary muscle).

Such fibers may be deposited by mounting of the electrospinning syringe,spinneret or tip onto a 5 or 6 DOF robotic arm, or onto a 5 axismachining center such as a mill, or by mounting the syringe on a linearslide and the substrate haptic onto a 4 axis (3 axes and one rotatingaxis). The haptic would need to be between the spinneret or syringe ortip and a grounded electrode. In this way several layers may bedeposited. Fibers in this case serves as a simple example, as bychanging the dimensions and shape of a spinneret, differentcross-sections of electrospun material can be formed such as ribbons.

Alternatively the electrospun fibers or membrane may be depositeddirectly onto a mold and then the haptic would be overmolded and in thisway also encapsulate the fibers.

Encapsulation may be a requirement to prevent leakage current due tocontact with the aqueous humour.

Triboelectric Energy Harvesting and Motion Sensing

The energy harvesting mechanism may in a further embodiment utilize thetriboelectric effect, or contact electrification. Different materialshave different charge affinities, and are ranked in a triboelectricseries. Contact between materials on the positive end of the list with amaterial on the negative end of the list passes charge between them andcan be stored in a capacitor or battery. It has been proposed thatunequal effective work energy levels of the materials enable anextraction of electrons by the Schottky and/or tunnelling effect, fromthe energy level of one material to the other. A general rule has beenproposed that for two materials, the material with the higher dielectricconstant will become positively charged when contact occurs between thetwo materials. Others have suggested that ions rather than electrons aretransferred for some materials.

In some embodiments of the present invention, a suitable pairing ofdifferent materials may be compressed or rubbed against each other by(for instance) the relaxing ciliary muscle, such that the friction oradhesion force, and subsequent separation force during the contractionof the muscle, create a periodic electrification of the materials.

The necessity of mechanical contact between the materials may be avoidedby use of materials with electret properties such as fluoropolymers(examples of which may be polytetrafluoroethylene, fluorinated ethylatedpropylene or perfluoroalkoxy alkane). In such materials, surface orspace charge storage is possible and can be maintained over long periodsof time, thus frictional charge transfer between materials may not benecessary for electrostatic induction.

A negative charge affinity material such as positively poled β phasePVDF, positively poled β phase PVDF-TrFe, PDMS, PET, PTFE, FEP and apositive charge affinity material such as PHBV, negatively poled β phasePVDF, negatively poled β phase PVDF-TrFE, Nylon may be used asnon-limiting examples.

Conductors on the ends of the opposing materials direct the current tostorage components (such as component 702 of FIG. 7) and an A/Dconverter such as convertor 701. In some embodiments, the energyharvester may itself serve as a storage component.

The negative and positively charged materials are preferablyencapsulated so that the aqueous humour, which contains electrolytes, isnot in contact with the energy harvesting components. The electrolytesmay discharge and/or mask the surfaces, preventing their efficientfunction.

The larger the surface area of the contact, the better to increase thetransferred charge. In one embodiment the two surfaces in contact arecomprised of electrospun fiber mats, either randomly deposited oraligned. The mats may be deposited on a conducting substrate such asPEDOT:PSS or any other conductor. Alternatively the surfaces may be thinfilms, micropatterned to increase the surface area. This can be achievedby creating a mold with high roughness and casting a material into themold. The mold can be a metal mold treated by hydrochloric acid forexample, and the cast material can be PDMS, fluoropolymer dispersions orPVDF. Transparency is not a requirement in the haptic area.

Since the energy harvesting component is hermetically sealed by itsencapsulation to avoid contact with electrolytes in the aqueous humour,metallic conducting materials with higher conductivity may be used, suchas silver or gold pastes, coatings, nanoparticles or nanowires or thelike.

A relatively more rigid (though still flexible and foldable) substratemay support the energy harvester components, against which the ciliarymuscle force may be applied. This rigidity directs the majority of thestrain to driving the components together so that the maximal energyoutput is achieved.

FIG. 6d-f show a triboelectric generator in cross section. Substratematerial 634 on the anterior side of the haptics serves as a stator inorder to avoid iris chafe. A moving substrate 633 on the posterior side,serving as a mover, may move e.g. in the direction specified by thearrow 632. The entire assembly fitting in the sulcus may in one examplebe between 50-250 micrometers thick.

Between the two mentioned layers 634, 633 may be located conductinglayers or electrodes 635 and 636 on the posterior and anterior sides,respectively. Each layer 635, 636 may be deposited with nanostructures(possibly electrospun nanofibers or other nanostructures possibly formedby casting in a mold) of negative and positive affinity materials withdifferent placing on the triboelectric series. For example, a negativecharge affinity material 637 may be e.g. an electrospun PVDF fiber or afluoropolymer electret, and a positive charge affinity material 638 maybe e.g. at least one of PEDOT, PEDOT:PSS, PET, Nylon, Silver nanowires.

In FIGS. 6d to 6g , movement is shown for one small perturbation on theorder of the diameter of the fibers. The movement may cause electrontunnelling from the energy level of the negatively charged 637 to thepositively charged 638 material, creating a positive charge 653 on theanterior electrode 636. In FIG. 6d , the negative charge affinitymaterial 637 may come in contact with positive charge affinity material638 and transfers electrons to it. A net positive charge in the negativecharge affinity material is caused and a net negative charge in thepositive charge affinity material. Since momentarily the two surfaces637 and 638 are in full contact over their surfaces, the overall chargeis balanced and the current is substantially zero.

When a lateral force in the upward direction 632 (as shown in FIGS. 6eand 6f ) is exerted on the mover, a separation is gradually causedbetween the negative and positive charge affinity materials, with a gapforming between the nanostructures on both sides of this gap. Thecharges that were transferred are retained in each material, as they areinsulating materials. Now that the surfaces are no longer in contact, anelectric potential is formed between the electrode layers.

Current is proportional to changes in the voltage over time as is knownto those skilled in the art. The graphs above each respective FIGS. 6dto 6g schematically show the current 630 at each point in time. The loadbetween the electrodes that forms part of the energy harvestingcircuitry described previously is not shown for simplicity.

As described above, the current 631 in FIG. 6d is zero when there is novoltage change caused by no movement. Next, in FIG. 6e , movement as inthe direction shown by the arrow 632, the current 639 is becoming largeras the contact area decreases towards full separation in FIG. 6f , andmaximal current 640. FIG. 6g shows the current decreasing 641 as thecontact area once again gradually increases and the overall charge iseventually balanced at full overlap. Thus an alternating current iscreated.

Alternatively, in another embodiment, one of the materials 637 or 638may be a conducting material, possibly with a different placing in thetriboelectric series than the opposing insulating material. Forsimplicity, the negative charge affinity material. The charge imbalancedescribed above in which the charge is retained when the materials comeout of contact, is reduced due to the conducting nature of the negativecharge affinity material, and the current returns to zero at this point.In essence, the harvesting frequency is effectively doubled in thisarrangement. In addition, the construction of theelectrode-insulator-electrode arrangement of this embodiment may besimpler to manufacture compared to theelectrode-insulator-insulator-electrode arrangement described above inthe previous embodiment. In the case of an electret material used as oneof the materials 637 or 638, when the ciliary muscle reaches maximaldisplacement at full accommodative effort, it may be preferable thatthere be maximal overlap of materials to maintain a constant DC electricpotential in order to maintain an actuated state of the lens.

FIGS. 6h and 6i are non-binding examples of an embodiment of a possibleform the lens may take with an integrated triboelectric energyharvesting mechanism on the haptics, in this case plate haptics. Theangulated haptics 645 are in contact an optic body such as abovedescribed embodiments 100, 3000, optionally comprised of an anteriorlens 648, a posterior lens 647 and a cavity filled with aqueous humour649 that can enter via a fenestration 646. The optic body, althoughdescribed with respect to an optic body arrangement (such as arrangement3000), may also be a single lens arrangement such a single actuatinglens such as in optic body 100.

Mounted on the haptics and encapsulated (encapsulation material notshown) may be a thin layer 643, and between the haptics and this layer(made of for example, acrylic material) may be an aformentioned energyharvester as in FIG. 6d-g , formed of an electrode layer, positivelycharged nanofiber layer, negatively charged nanofiber layer, and finallyanother electrode layer. The nanofibers being encapsulated preferablyhermetically, have substantially no contact with the electrolytes in theaqueous. Several projections 644 may be in contact with the ciliarysulcus, creating a minimal pressure on the surrounding tissue andenabling the adaptation of the energy harvesting mechanism to variousdiameters of ciliary sulcii (e.g. for different patients). The ciliarymuscle pushes against the projections 644 and then relaxes in directionsof double pointed arrow 652 (i.e. pushing in down and relaxing is up inarrow 652) leads to intermittent contact between the nanofibers,creating a charge as described above with respect to FIGS. 6d-g . Therelaxation of the ciliary muscle which increases its diameter, allowsthe energy harvesting mechanism to return to its previous shape due tothe elasticity of the encapsulant material.

FIG. 8 shows a cross section of an optional embodiment of the lens opticand haptics, with the sliding encapsulated mover 800 and stator 802. Themover 800 possibly here ends in a protrusion, possibly bent protrusion(see enlarged section to the right of FIG. 8) so as to be in contactwith the ciliary muscle, while the stator part 802 of the haptics isinside the ciliary sulcus. This embodiment enables support of the lens,while allowing for movement of the mechanism without causingdecentration with respect to the line of sight. An angle 803 (Ang 1) anda length dimension 804 (D2) are typical dimensions of the ciliarysulcus, where Ang 1 is approximately 65° and D2 is approximately 0.5 mm.

FIG. 8a shows the position of an embodiment of FIG. 8 in the eye. Thestator part of the haptic is in contact with the ciliary sulcus 820while the mover part 822 is in contact preferably with an anterior partof the ciliary process 821. Other structures are the iris 823, zonules825 and the outline of the capsular bag 824 when filled with thecrystalline lens, which is no longer present after phacoemulsification,leaving the capsular bag 824 collapsed.

Both the ciliary sulcus and the ciliary process move radially inward(i.e. towards the optical axis) during accommodation, releasing tensionin the zonular fibers. There may be benefit in having as large arelative motion as possible between the stator and mover which directlyaffects the energy harvested. The stator part of the haptics in anembodiment is designed to absorb the motion of the ciliary muscle,keeping the lens in the same position, while the mover transmits theforce of the ciliary muscle to movement of the energy harvestingmechanism.

A possible method to absorb the movement may be by creating a resilientmember 830 at an outer radial portion of the stator haptic 802, herepossibly shown having a cantilever-like shape as in C-loop haptics, (seeFIG. 8b ). The mover part 831 of the haptic is here separated from thestator 802 close to the contact area with the ciliary muscle, so thatresilient member 830 absorbs movement from the muscle fibers in theciliary sulcus to substantially allow stator 802 to remain in place,while mover 831 exposed to movement of the ciliary muscle (preferably ananterior part of said muscle) is left to move to facilitate harvestingof energy.

A similar embodiment can be realized for an intraocular lens beingimplanted in the capsular bag (see 824 in FIG. 8A), in which the energyharvesting mechanism may be positioned to take advantage of movement ofthe capsular bag tissue caused by the ciliary muscle, against thehaptics. In FIG. 8c , this case is shown in which a stator part of thehaptics 846 may possibly be positioned to be in contact with the equator847 of the capsular bag and a mover 843 may be in contact with theanterior portion 840 of the capsular bag and the posterior portion 842of the capsular bag (shown here only in contact with the anteriorportion 840 of the capsule) and move in proximity to an additionalstator 844, to absorb the stretching movement of the capsule in theaxial direction (movement direction shown by arrow 845, capsule isstretched in the transverse direction shown by arrows 848). Thecapsulorrhexis is not shown in this drawing.

In essence, the functional mechanism of the energy harvesting componentswhether implanted in the ciliary sulcus or the capsular bag issubstantially similar, in this example differing in the vectors ofmechanical forces and the resulting geometry of the stator and mover tobest utilize these forces.

Adjustable Haptics

In some embodiments the overall structure of the haptics may beadjustable in their total diameter so that they may be configured toexert substantially similar force when in contact with different ciliarysulcus or capsular bag sizes, for example by way of a sliding mechanismthat is locked in a rigid manner once reaching the desired position.

FIGS. 9a and 9b schematically illustrate an aspect of the presentinvention where an embodiment may be provided in which a haptics 900(possibly a haptics including energy harvesting components but notnecessarily) may be connected to an optic body 100 via adjustablecoupling means 901. The coupling means 901 may include first members 907on the haptics that are configured to couple with respective secondmembers 908 on the optic body 100.

The first members in this example may take a form of struts with teethlike formations that are configured to be received in respective teethformations on the second members to form a ratchet like meshingmechanism 904.

A surgeon may manipulate the position of the haptics relative to theoptic body, by urging the first and second members to slide one inrelation to the other in order to slightly bias the haptics away ortowards the optic body. In the possible ratchet like meshing mechanism904 this may be facilitated by slightly expanding a distance between theteeth on the struts of the optic body in order to enable the teeth ofthe haptic struts to progress to a subsequent position enabling eitherthe haptics to bias closer or further away from the optic body.

Such adjustable coupling means 901 may be used to attach an optic bodyto haptics including energy harvesting means in order to enable fineadjustment of the position of the haptics relative e.g. to the ciliarymuscle in order to optimize the force exerted by the muscle e.g. on amover (such as mover 800) so that it may efficiently move against astator (such as stator 802 seen in previous embodiments). Such fineadjustment, which on the one hand enables fine tuning of the hapticsrelative to the muscle, substantially does not change the overallposition of the haptics (possible with energy harvesting mechanism)relative to the optic body for a given ciliary muscle diameter of acertain patient.

In an embodiment, the adjustable coupling means may include stoppers 902and 903 on the first members 907 and corresponding stoppers 905 on thesecond members 908 of the optic body, in order to constrain the range ofadjustment and by that avoid e.g. detachment of the haptics from theoptic body.

Limiting the range of adjustment may facilitate adjustment of theoverall diameter of the IOL within a given range, possibly between about9.5mm and about 13mm, covering typical requirements for most patients ofall ages. This embodiment may be advantageous in the case of IOLimplantation in children or in ageing patients, where the natural growthof the eye may change the ciliary muscle diameter, or correction forweakening ciliary muscle may be performed, e.g. in secondary procedureslater in life.

In one or more embodiments additional flexible struts may beincorporated into the optic-haptic junction to allow for wiring or othermeans of electrical communication between the energy harvestingmechanism and the optic body/actuating mechanism.

In addition said adjustable haptics may be implemented in conjunctionwith any IOL, not necessarily having an energy harvesting mechanism oran actuating lens, where simple surgical manipulation with standardtools such as Sinskey hooks, Kuglen hooks, choppers, spatulas, holdersor forceps may adjust the overall diameter of a lens by increasing theseparation distance between said haptics and optic body to fit the IOLin various ciliary sulcus and/or capsular bag sizes, pre-empting e.g.the need for pre-operational ultrasound biomicroscopy (UBM) measurementsto determine said sizes, and reducing the need for various diametersizes of an IOL.

Signal Processing, Energy Storage and Control

An embodiment of a motion sensor 700 is shown in a lumped diagram inFIG. 7.

In an embodiment energy harvested by the motion sensor 700 may be storedin an energy storage component 702 such as a miniaturized capacitor or abattery, or plurality of the same, embedded in the lens material outsideof the clear optic, and serving as a power source.

In one embodiment of the invention, the operation of the actuating lens705 is controlled by a microcontroller 703 embedded in the lens bodymaterial, in an area that is outside of the clear optic diameter.

An analogue to digital (A/D) converter 701 may be employed to quantizethe input voltage from the motion sensor 700 possibly by receivingenergy from energy storage 702 for its function. The quantized signal isin turn passed possibly to a digital signal processor (DSP, not shown)for passing the correct logic to the microcontroller 703. Possibly,microcontroller 703 may define said logic. Microcontroller 703 inaddition may receive energy from storage 702 for its function. Athreshold required to induce motion in an actuating lens and/or tomaintain the actuated state may be defined according to a value of oneor more of such quantization steps.

Regarding the number of steps in the quantization of the input signal,taking 4D as a nominal value of the maximal change in focus, and amaximal acceptable refractive error at the lens plane of 0.5D, the A/Dconverter may have 8 steps, or be a 3 bit converter as a minimalrequirement. A 4 bit converter gives 0.25D steps, which may bepreferred. At this resolution there is little significance from apatient perception to the quantization error.

Once an accommodative response is sensed by the motion sensor 700, theelectric signal is directed to the microcontroller 703 which in turncauses the energy storage 702 to direct a current into the actuatinglens circuit 705. This creates the deflection and curvature changerequired in the actuating lens. Signal generator 707 may generate an ACsignal depending on the resonant frequency of a piezoelectric actuatoror DC signal in the case of a dielectric elastomer actuator. In somecases, excess energy above a certain step not reaching a level of asubsequent higher step may be conserved in energy storage 702 and notexpended to create the deflection and curvature change in the actuatinglens.

A low pass filter may be incorporated in the microcontroller logiccircuitry to provide a clear trigger signal for actuation, be itfar-to-near or near-to-far accommodation depending on the sign of theinput.

Motion of the actuated lens would also create an electrical signal,either by way of the inverse piezoelectric effect or by capacitancechanges stemming from changes in the plate separation distance duringactuation. Such a signal would result in a reverse current, also guidedby the circuitry 706 to the energy storage components. A diode may beused for this purpose. Thus the energy used by the actuating lens may beconserved.

All circuitry may be part of the lens and embedded into the lensmaterial.

It may be necessary to create varied curvature responses to differingaccommodative demands both for piezoelectric or dielectric elastomerbased lenses. In the case of a piezoelectric based lens, this may beachieved by supplying power in one or more AC frequencies possibly withdiffering amplitudes and/or DC offsets, provided by a signal generatorpossibly similar to signal generator 707. In the case of a dielectricbased lens, a DC voltage in differing magnitudes across theelectroactive material layer (EAM) may create such varied curvatures.

In an embodiment of a piezoelectric based lens, provision of the ACvoltage may be with a non-zero (possibly negative or positive) DC offsetcorrelating to the required or targeted lens curvature, with such DCoffset urging the lens away from its resting state, possibly against thelens elasticity acting to urge the lens back to it resting state.Frequency may depend on variable factors such as stiffens of lens andgeometry of the lens.

Different accommodative responses may be expressed in the variance inchanges of the ciliary muscle ring diameter (CMRD), as well as otherstructures that are part of the ciliary process that the sensor maydetect. Calibration and/or setting of the threshold for each discretizedposition of the ciliary muscle vs EAM layer deflection in an embodimentis suggested by way of prior measurement of the typical amplitude ofmotion of a given patient by using Anterior Segment Optical CoherenceTomography (AS-OCT). This may be performed immediately after removingthe cataractous lens. In a non-binding example this “binning” ofthreshold levels may be decided in advance, for instance by using anaverage value between 0.02 mm and 0.105 mm in change of CMRD per diopter(D). Possibly, the setting of the threshold may be affected byconsiderations such as manufacturing and/or design considerationsstemming e.g. from an EAM and/or substrate layer thickness, number ofEAM and/or substrate layer (etc).

Near Infrared Energy Harvesting

In another aspect of the energy harvesting method, the energy may beharvested from a series of photovoltaic cells that absorb near infra-redlight, of wavelengths between 750 nm and 900 nm. These wavelengths arenot significantly absorbed by the skin, bone and eye tissue, especiallynot in the typical tissue depths from between the outside world and upto the IOL. This is a source of energy that is useful for harvestingduring daylight hours, in which approximately 50% of light reaching theeye is in the IR range. Since visible light would only go through thepupil, the relative amount of energy of unabsorbed NIR light would bemuch higher.

While UV light is also prevalent, in the crystalline lens and in mostIOL materials it is blocked or filtered, as UV is one of the causes ofcataracts and is harmful to the retina. In addition to this the lifetimeof UV-absorbing photovoltaic cells would be shorter than at working atother wavelengths, which is undesirable in a biomedical implant.

The photovoltaic cells may be anywhere on the lens body outside theclear optic, in a manner that does not interfere with the actuation ofthe lens or encumber the folding or injection of the lens. Thephotovoltaic cells would preferably be biocompatible, and in any case beembedded in the lens material, which is transparent to NIR wavelengths.

In an embodiment the light energy arriving through the pupil may beabsorbed by a transparent dye or dye suspension, formed in between ananterior NIR-transparent layer and posterior NIR-reflective layer, andforms a waveguide. The anterior and posterior layers are bothtransparent to visible light. The NIR light is absorbed in this dyelayer, and then via the Stokes shift the dye emits light at another NIRwavelength that is guided to the photovoltaic cells.

The lens may be packaged in a preloaded injector or delivery devicewhich enables simple use and delivery into the eye, preferably through asmall incision in the cornea or limbus as is known to those skilled inthe art.

In the description and claims of the present application, each of theverbs, “comprise” “include” and “have”, and conjugates thereof, are usedto indicate that the object or objects of the verb are not necessarily acomplete listing of members, components, elements or parts of thesubject or subjects of the verb.

Furthermore, while the present application or technology has beenillustrated and described in detail in the drawings and foregoingdescription, such illustration and description are to be consideredillustrative or exemplary and non-restrictive; the technology is thusnot limited to the disclosed embodiments. Variations to the disclosedembodiments can be understood and effected by those skilled in the artand practicing the claimed technology, from a study of the drawings, thetechnology, and the appended claims.

In the claims, the word “comprising” does not exclude other elements orsteps, and the indefinite article “a” or “an” does not exclude aplurality. A single processor or other unit may fulfil the functions ofseveral items recited in the claims. The mere fact that certain measuresare recited in mutually different dependent claims does not indicatethat a combination of these measures cannot be used to advantage.

The present technology is also understood to encompass the exact terms,features, numerical values or ranges etc., if in here such terms,features, numerical values or ranges etc. are referred to in connectionwith terms such as “about, ca., substantially, generally, at least” etc.In other words, “about 3” shall also comprise “3” or “substantiallyperpendicular” shall also comprise “perpendicular”. Any reference signsin the claims should not be considered as limiting the scope.

Although the present embodiments have been described to a certain degreeof particularity, it should be understood that various alterations andmodifications could be made without departing from the scope of theinvention as hereinafter claimed.

1.-113. (canceled)
 114. An intraocular lens (IOL) comprising a clearoptic, preferably comprising a polymer, and an actuator for actuatingchange in curvature in at least a portion of the clear optic, the IOLcomprising in addition a substrate and the actuator is formed on anouter side of the substrate, wherein the actuator comprises a pair ofnegative and positive electrodes and an electroactive material (EAM)being at least partially in contact with the electrodes, and whereinchange in curvature is formed by applying voltage between theelectrodes.
 115. The IOL of claim 114, wherein the electrodes comprisetransparent material, and are preferably formed in contact withdifferent areas of the clear optic.
 116. The IOL of claim 115, whereinupon cessation of urge in curvature change the clear optic is configuredto elastically return towards a non-urged resting state, whereinpreferably a resting state is at least one of a convex-concave state orconcave-convex state.
 117. The IOL of claim 116 and comprising relativeanterior and posterior portions spaced apart by a cavity and theactuator assisting in urging change in curvature is in at least one ofsaid portions.
 118. The IOL of claim 117, wherein said relative anteriorand posterior portions being connected by a bridge formed about at leasta portion of a periphery of the IOL, wherein the bridge preferably beingformed with passages or fenestrations for providing fluid communicatingbetween the cavity and an exterior medium outside of the cavity,possibly with a fluid reservoir not in contact with the aqueous humourof the eye.
 119. The IOL of claim 118, wherein the electroactivematerial comprises a piezoelectric polymer and/or a dielectric elastomermaterial.
 120. The IOL of claim 119, wherein the actuator comprising astack of electroactive material layers (EAMs) with interdigitatedelectrodes, wherein preferably adjacent electrodes being oppositelycharged.
 121. The IOL of claim 119 wherein the electroactive materialcomprises a dielectric elastomer material which is a soft and passivedielectric material with a high Poisson ratio, sandwiched betweencompliant electrodes.
 122. The IOL of claim 121 wherein the electrodesare transparent conductors covering the surfaces of the dielectricelastomer material.
 123. The IOL of claim 121 wherein the electrodes aresilver nanowires patterned over the surfaces of the dielectric elastomermaterial, without decreasing the transmission of light through the lensto below 90% in the visible range.
 124. The IOL according to claim 114and comprising a haptics for coupling to an optic body of the IOL,wherein the haptics comprising a motion sensor incorporated therein fordetecting motion in at least a portion of the haptics, and wherein themotion is due to an accommodative response in an eye in which the IOL isconfigured to be placed.
 125. The IOL of claim 124 wherein the hapticscomprising a triboelectric generator, possibly including an electretmaterial, for harvesting energy, preferably forming and/or being part ofthe haptics, wherein the generator preferably comprising a statorelement possibly on an anterior side of the haptics, preferably in theform of substrate material, and a moving element possibly on a posteriorside of the haptics, preferably in the form of substrate material. 126.The IOL of claim 125, wherein the generator being configured to fit intoand/or interact with the ciliary sulcus or capsular bag of an eye inwhich the IOL is to be placed.
 127. The IOL of any one of claim 126,wherein at least one of the stator element and moving element comprisingand/or being coupled with a respective conducting layer or electrode.128. The IOL of claim 127, wherein each conducting layer or electrodecomprising nanostructures, possibly electrospun nanofibers or othernanostructures, of negative and positive affinity materials withdifferent placing on the triboelectric series.
 129. The IOL of claim128, wherein stator element being configured for contact with theciliary sulcus and the moving element being configured for contact withan anterior part of the ciliary process when the IOL is placed in theciliary sulcus implant location, or wherein a stator element beingconfigured for contact with the equator of the capsular bag and themoving element being configured for contact with the anterior andposterior capsules of a capsular bag of the eye, to move in proximity toan additional stator component.
 130. The IOL of claim 129, wherein thestator element being configured to absorb the motion of the ciliarymuscle for keeping the IOL in substantially the same position, and themoving element being configured to transmit force of the ciliary muscleto movement of the generator for harvesting energy.
 131. The IOL ofclaim 130, wherein an electric potential being formed across a gapbetween the stator and moving element, and said gap being preferablyhermetically sealed from contact with an aqueous humour of an eye inwhich the IOL may be placed.
 132. The IOL of claim 131, whereinharvested energy is stored in an energy storage component for possiblymaintaining an actuated state of clear optic, wherein output of energyis only when the voltage is above a threshold, preferably pre-definedthreshold.
 133. The IOL of claim 132 and comprising a converterconfigured to quantize input voltage from the motion sensor intoquantization steps, by preferably receiving energy from energy storagecomponent for its function, wherein the quantized signal is preferablycommunicated from the converter to a microcontroller.
 134. The IOL ofclaim 133, wherein the overall structure of said haptics is adjustablein their total diameter so that they are configured to exertsubstantially similar force when in contact with different ciliarysulcus or capsular bag sizes of different patients, by way of a slidingmechanism that may be locked in a rigid manner once reaching the desiredposition.
 135. A haptics for coupling to an optic body of an intraocularlens (IOL) and comprising a triboelectric generator for harvestingenergy, preferably forming and/or being part of the haptics, wherein thegenerator comprising a stator element possibly on an anterior side ofthe haptics, preferably in the form of substrate material, and a movingelement possibly on a posterior side of the haptics, preferably in theform of substrate material.
 136. The haptics of claim 135, wherein thegenerator being configured to fit into and/or interact with the ciliarysulcus or capsular bag of an eye in which the IOL is to be placed. 137.The haptics of claim 136, wherein at least one of the stator element andmoving element comprising and/or being coupled with a respectiveconducting layer or electrode.
 138. The haptics of claim 137, whereineach conducting layer or electrode comprising nanostructures, possiblyelectrospun nanofibers or other nanostructures, of negative and positiveaffinity materials with different placing on the triboelectric series.139. The haptics of claim 135 and comprising an energy storage componentfor storing harvested energy, wherein the energy storage component is atleast one miniaturized capacitor and/or at least one battery, possiblyconstituting at least part of the motion sensor.
 140. An intraocularlens (IOL) comprising haptics, an optic body and adjustable couplingmeans for permitting relative adjustment between at least a portion ofthe haptics and the optic body, wherein the overall structure of saidhaptics may be adjustable in their total diameter so that they areconfigured to exert substantially similar force when in contact withdifferent ciliary sulcus or capsular bag sizes of different patients, byway of a sliding mechanism that may be locked in a rigid manner oncereaching the desired position.
 141. The IOL of claim 140 wherein theadjustable coupling comprising first members on the haptics and secondmembers on the optic body, wherein each first member is configured tocouple to a respective second member.
 142. The IOL of claim 141, whereineach first member is slideable relative to its respective second member.143. The IOL of claim 142 and comprising energy harvesting means atleast partially located on the haptics.
 144. The IOL of claim 143,wherein adjustment between the haptics and the optic body is in order topermit optimal placement of the haptics relative to an eyeportion/component where the IOL is supported.